The character is head over heels of him -or herself. He/she might be the best(or not) , but usually the laziest to act and always underestimates the enemies. Rather popular concept for villains and rivals.

Used frequently in Anime to either recap past events or provide a back story for a character, either their origin story or their off-screen training of new attack. Sometime and entire episode/chapter would be a entire flashback.

Humans are typically depicted as the dominant species of the planet Earth, and sometimes of other planets. Humans often mirror their real life counterparts in terms of abilities and intellect, while other times they can achieve superhuman feats.

Characters who exercise their strong libidinous desires in unwholesome ways, such as peeping on the objects of their desire, making inappropriate comments, stealing underwear etc.
Though typically middle-aged or elderly men with a penchant for young girls, there are probably a few dirty old women out there.